| abstract |
A polyurethane foam is obtainable from the reaction of a mixture comprising A) an isocyanate-reactive compound; B) a blowing agent selected from the group comprising linear, branched or cyclic C 1 to C 6 hydrocarbons, linear, branched or cyclic C 1 to C 6 fluorohydrocarbons, N 2 , O 2 , argon and / or CO 2 , wherein the blowing agent B) is in the supercritical or near-critical state; and C) a polyisocyanate. The isocyanate-reactive compound A) comprises a hydrophobic part and has a hydrophilic part and an average hydroxyl functionality of more than 1. The hydrophobic part comprises a saturated or unsaturated hydrocarbon chain having at least 6 C atoms and the hydrophilic part comprises alkylene oxide units and / or ester units. Very preferred as component A) is a sorbitan ester according to formula (II): with w + x + y + z = 20. |